"Deal with" multiple respositories? That's a completely normal and expected configuration, and not something you deal with. You don't describe your experiences

"Deal with" multiple respositories? That's a completely normal and expected configuration, and not something you deal with. You don't describe your experiences in detail but it sounds like if you have snowflake requirements where you need to track up-upstream closer, that you're better off building the source debs. The part where you write off verification checks as also sounds like it is based on a misunderstanding. It is something you do for audit requirements, not something you "rely security on". It is something most professionals would have come into contact with at least once.